It is considered desirable to provide glassy, amorphous and/or crystalline material which possesses phototropic or photochromic properties. Particular utility for such a product is found in sunglasses. As is wellknown, there are two primary markets for sunglasses; namely, Rx or prescription and plano. The plano is usually a less expensive product which may be used by those persons not requiring vision correction. The Rx lens is used by those requiring correction. The present invention has utility in either the Rx prescription or plano market. It is also usable with image display and storage systems, photochromic windows, and the like.